Manufacture of smoking products



United States Patent 3,121,433 MANUFACTURE 0F SMOKING PRODUCTS RichardAllan Plunhett, Decatur, Ill., and Albert Cornwell Shuman and Roy LesterWhistler, West Lafayette,

[ml., assignors to American Machine & Foundry Company, a corporation ofNew Jersey No Drawing. Filed Au". 8, 196 1, Ser. No. 130,192

2 Ciaims. (Cl. 131140) This invention relates to the manufacture oftobacco sheet material. More particularly, the invention concerns atobacco sheet made substantially entirely from tobacco material of whicha major proportion is dry ground.

Tobacco sheet, has heretofore been made by combining tobacco dust. witha minor amount of film forming adhesive material such as polysaccharideemulsions. The use of dry ground rather than wet colloid milled tobaccohas been recognized in this work as the basis for a sheet of superiorburn aroma.

Prior to the development of tobacco sheet based on dry ground tobaccodust suspended in a polysaccharide adhesive matrix, work was done bothon the manufacture of paper from tobacco and on the formation of sheetsfrom wet milled tobacco particles.

Both of the latter types of sheet were made almost entirely from tobaccobut lacked the burn aroma of a sheet made from a preponderant amount ofdry ground tobacco. The burn odor of the polysaccharide bound sheets wasinfluenced by the odor of burning adhesive. No tobacco sheet hasheretofore been described which combines the virtue of dry groundtobacco with freedom from adhesive burn aroma.

Therefore, it is an object of this invention to provide a tobacco sheetmaterial which includes a preponderant proportion of dry ground tobaccoand is made substantially entirely from tobacco.

Another object of the invention is to provide a method of making tobaccosheet material which includes a preponderant proportion of dry groundtobacco and is made substantially entirely from tobacco.

These and other objects of the invention are more fully set forth in thefollowing detailed description of the invention.

It has been found that tobacco contains within the plant tissue asubstantial amount of adhesive material which can be used to bindtogether particles of dry ground tobacco dust. Much of this adhesivematerial includes polysaccharides of the hemicellulose or polyuronidegroups and in the latter case largely pectins and related compoundswhich can be insolubilized by calcium ions. These materials can bereleased from the plant tissue by suitable chemical and physicaltreatment and combined with dry dust to form a sheet.

Tobacco material is steeped in water and cooked, preferably underpressure. The cooked material is treated in a beater with enough alkalito break down plant tissue and release adhesive constituents. A viscouspulp is formed which is then acidified and combined with a large amountof tobacco dust.

The mixture of pulp and dust is then formed into sheets on a sheetingmachine such as a metal plate, band, or fine screen. All of these typesof machine have been described in the tobacco sheet art.

Novel features of this invention include the treatment of stem fiberwith caustic together with subsequent neutralization by acid to form asalt found naturally in tobacco which, moreover, aids in burn control ofthe sheet, such as saltpeter.

Another feature of the invention is the use of a major proportion of dryground tobacco with a minor amount of stems from which a naturaladhesive is extracted.

The stems are macerated and the fibers are very finely chopped comparedwithv paper-making methods.

A cross-linking agent such as a dialdehyde like glyoxal or calcium saltsis added to the pulp slurry to give wet strength to the sheet byreaction with tobacco polysaccharides according to a preferred form ofthe invention.

The following example and recipe illustrates a preferred embodiment ofthis invention. While all of the adhesive chemicals used are derivedfrom tobacco, the use of small amounts of non-adhesive ingredients suchas humectants, waterproofing cross-linking. agents and salts found innatural tobacco will greatly improve the utility of the final product assmoking material filler in pipes, cigars and cigarettes.

Example Twelve grams of cigar stems (approximately 10 grams ash-free dryweight) and 1-00 to 250 ml., preferably 200 ml., of water are placed inan 800 ml. beaker, covered with a watch glass and placed in an autoclaveor pressure cooker. Other containers may be used. The cover serves toreduce somewhat the loss of water from the beaker during the cooking.The loss may just as well be made up later. The autoclave is heated, forexample, to about 15 p.s.i.g. which corresponds to a temperature ofabout 120 C. and held there for 10 to 20 minutes, preferably 10 minutes.The swollen and softened stems are cooled to 20 to 40 C. and beaten 10to 30 minutes, preferably 15 minutes, in a high speed blendor.

Stronger sheets result when the temperature is not allowed to go toohigh, to C., during the beating operation when the pulp is beingintimately mixed with air. This is probably even more important afterthe alkaline autoclaving.

Any water losses which may have occurred during the first autoclaving orthe beating are made up and 0.75 gram of potassium hydroxide (85% assay)is mixed in thoroughly. The mixture is autoclaved 2 to 18 hours,preferably 4 hours, at 15 p.s.i.g. and cooled. The pulp is beaten about30 minutes or somewhat less in a blendor.

The pulp is next adjusted to pH 4.3 with dilute nitric acid (1 vol. 70%nitric acid to 1 vol. water) and preferably 0.6 gram of glycerin andpreferably 2.5 grams of 30% glyoxal are added and mixed in thoroughly.Glycerin and glyoxal in very small amounts improved the sheet but may beomitted. Other humectants such as diethylene glycol or polyalclehydecross-linking agents may be substituted. The pulp is finally adjusted topH 2.62.8 with dilute nitric acid. It would also be satisfactory firstto adjust the pH to 2.6-2.8 and then add the glycerin and glyoxal.

Finally 28.5 grams of -80 US. standard mesh Connecticut Broadleaftobacco dust (-50 mesh is not as satisfactory) and sufiicient water,about ml., to give a consistency similar to that of catsup are added.The slurry is now ready to be cast in a sheet. The dry sheet thusproduced will have the following approximate composition:

In regard to the steam pressures and temperatures recommended, care mustbe taken to insure uniform heating of the batch of stems.

Some bright tobacco stems require 2.0 grams of KOH per 12 grams of stemto give a pH of 8.0 to 9.0 after the final beating. This is almost threetimes the amount of 'alkali usually required. Other samples of burley,bright and cigar tobaccos work satisfactorily with 0.75 gram of KOH per12 grams of stems. A titration method can be used to determine theamount of alkali required by any batch of stems.

There has been described a new tobacco composition of dry ground tobacco(preferably in major proportion by weight) in combination with alkaliextracted tobacco pulp and very small amounts of humectant and salt.This material is formed into sheets which are shredded to provide fillerfor smoking articles.

What is claimed is:

1. The method of making tobacco sheet which com prises cooking a mixtureof tobacco in water, adding potassium hydroxide to the cooked tobaccomixture and further cooking same, acidifying the cooked tobacco mixturewith nitric acid to form potassium nitrate therein, adding dry groundtobacco dust to form a slurry, forming said slurry into a sheet anddrying said sheet, where- :by the potassium nitrate formed in theproduct improves the burn characteristics of the finished sheet.

2. The method of making tobacco sheet comprising digesting tobacco stemsin an aqueous alkaline fluid to form a pulp, comminuting said pulp,neutralizing said pulp while preserving all tobacco substances thereofin situ, combining said neutralized stem pulp and tobacco substanceswith a preponderance of finely divided dry ground tobacco and across-linking agent to form a viscous slurry and forming said slurryinto a sheet.

References Cited in the file of this patent UNITED STATES PATENTS 64,591Stayman May 7, 1867 720,830 Marsden Feb. 17, 1903 1,068,403 Maier July22, 1913 2,485,670 Sowa et al Oct. 25, 1949 2,547,730 Arnold Apr. 3,1951 2,734,510 Hungerford et al. Feb. 14, 1956 3,012,915 Howard Dec. 12,1961 FOREIGN PATENTS 229,817 Australia Aug. 9, 1960 871,952 GreatBritain July 5, 1961

1. THE METHOD OF MAKING TOBACCO SHEET WHICH COMPRISES COOKING A MIXTUREOF TOBACCO IN WATER, ADDING POTASSIUM HYDROXIDE TO THE COOKED TOBACCOMIXTURE AND FURTHER COOKING SAME, ACIDIFYING THE COOKED TOBACCO MIXTUREWITH NITRIC ACID TO FORM POTASSIUM NITRATE THEREIN, ADDING A DRY GROUNDTOBACCO DUST TO FORM A SLURRY, FORMING SAID SLURRY INTO A SHEET ANDDRYING SAID SHEET, WHEREBY THE POTASSIUM NITRATE FORMED IN THE PRODUCTIMPROVES THE BURN CHARACTERISTICS OF THE FINISHED SHEET.